Ungrounded control of low energy analog (lea) voltage measurements

ABSTRACT

Systems and methods for measuring low energy voltage in a high energy transmission line electrode divider network. A floating reference voltage screen is positioned between a high energy transmission line electrode and a ground plate at a distance from the high energy transmission line electrode that is shorter than a distance between the ground plate and the floating reference voltage screen. A first conductive lead electrically couples the high energy analog transmission line electrode to a first input of a voltmeter that is connected to a controller. A second conductive lead electrically couples the floating reference voltage screen to a second input of the voltmeter. An alternating voltage drop is measured across the high energy transmission line electrode and the floating reference voltage screen by electronics of the voltmeter connected to the controller. The controller and the voltmeter are both disconnected from the ground plate.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/937,364, entitled “UNGROUNDED CONTROL OF LOW ENERGY ANALOG (LEA)VOLTAGE MEASUREMENTS” filed Mar. 27, 2018, which is incorporated hereinby reference in its entirety.

FIELD OF THE INVENTION

Embodiments generally relate to methods and systems for determiningvoltage levels in a high-voltage recloser switch.

BACKGROUND

Reclosers are utilized in power distribution systems at transmissionline electrodes to automatically close interrupter switches after theyhave opened due to a fault. Such interrupters may be used, for example,in utility power-transmission systems or power-distribution systems forrailway or industrial plants. A recloser includes a three-phase switchand may employ two voltages sensors per phase leg for monitoring voltageon the input and output transmission lines of the recloser. One voltagesensor monitors the input line to a switch for one phase leg, andanother voltage sensor monitors the output line from the switch for thesame phase leg. Thus, internal voltage sensors are located on both sidesof the interrupter for each phase leg.

A recloser controller may be housed in a frame a distance from arecloser switch. This distance may depend on the amount of electricalinsulation needed to isolate the recloser controller relative to thehigh-voltage recloser switch. The recloser controller receives voltagessensed by the voltage sensors via a control cable. Low energy analogvoltage levels may be detected in each sensor utilizing a passivevoltage divider circuit, for example, a capacitor network or componentsthat form a capacitor network. The voltage divider circuit may bedesigned to measure a specified low energy output voltage (Vs) relativeto earth ground. This low energy voltage is used to determine a highvoltage (HV) level of the transmission line relative to ground. Forexample, a line input value of HV=10 kilovolts (kV), could ideally yielda sensed output Vs=1 volt (V), for a ratio of HV/Vs=10 k/l.

SUMMARY

Within a recloser voltage sensor, a voltage divider network may beformed by capacitive elements positioned relative to a power lineelectrode, for example, a voltage screen that encircles the power lineelectrode, and an earth ground plate encircling the voltage screen. Thevoltage screen is made of a conductive metal. The interior of thevoltage sensor may be filled with a dielectric material. Conductiveleads from the voltage screen and the earth ground may be connected to avoltmeter at the recloser controller. A first capacitance may existbetween the ground plate and the voltage screen, and a secondcapacitance may exist between the voltage screen and the power lineelectrode. In high-voltage systems, the voltage screens are locatedcloser to the ground plates than to the power line electrodes so thatlow energy analog voltages are output across the screen to ground leadsand can be measured by electronics of the voltmeter at the recloser. Therecloser controller may determine a drop in voltage from the power lineelectrode voltage to earth ground based on the sensed voltage screen toearth ground output voltage and the capacitances of the voltage dividernetwork. However, a significant amount of electrical insulation isrequired in deployment of these systems, and the voltmeter and reclosercontroller must be located a relatively long distance from the highpower transmission lines.

Although the capacitive elements are described, with respect to oneexample, as cylinders relative to the power line electrode, thecapacitive elements are not necessarily cylinders and may have anothergeometry suitable to form a voltage divider network relative to thepower line electrode. For example, the capacitive elements by be formedas partial cylinders, plates, spheres or partial spheres, or othershapes. The capacitive elements are placed near each other with adielectric material between them. The dimensions and placement of thecapacitive elements may depend on the intended power system voltage,dielectric material used, and capabilities of a voltmeter used tomeasure the voltage. Also, although the screens the capacitive elementsare referred to as screen and a ground plate in one example, thecapacitive elements may be made of a conductive screen with holes, asolid conductive material, or a combination of screens and solidmaterials.

Certain embodiments are directed to a recloser floating referencevoltage sensor of a recloser controller, where the sensor includes avoltage divider network for measuring low energy analog voltage and thevoltage divider network and the recloser controller are disconnectedfrom ground.

In some embodiments, a voltage sensor system is provided to measure alow energy voltage in a high energy transmission line electrode dividernetwork. The system includes a high energy transmission line electrode,a floating reference voltage screen, and a ground plate. The floatingreference voltage screen is positioned between the high energytransmission line electrode and the ground plate at a distance from thehigh energy transmission line electrode that is shorter than a distancebetween the ground plate and the floating reference voltage screen. Afirst conductive lead electrically couples the high energy analogtransmission line electrode to a first input of a voltmeter that isconnected to a controller. A second conductive lead electrically couplesthe floating reference voltage screen to a second input of thevoltmeter. An alternating voltage drop is measured across the highenergy transmission line electrode and the floating reference voltagescreen by electronics of the voltmeter connected to the controller. Thecontroller and the voltmeter are both disconnected from the groundplate.

In some embodiments, a method is provided for measuring low energyvoltage in a high energy transmission line electrode sensor network. Themethod includes positioning a floating reference voltage screen betweena high energy transmission line and a ground plate at a distance fromthe high energy transmission line electrode that is shorter than adistance between the ground plate and the floating reference voltagescreen. The method also includes electrically coupling a firstconductive lead to the high energy transmission line electrode and to afirst input of a voltmeter that is connected to a controller. The methodfurther includes electrically coupling a second conductive lead to thefloating reference voltage screen and to a second input of the voltmeterthat is connected to the controller. The method also includes measuringan alternating voltage drop across the high energy transmission lineelectrode and the floating reference voltage screen by electronics ofthe voltmeter connected to the controller. The controller and thevoltmeter are both disconnected from the ground plate.

In some embodiments, a system is provided for determining high energytransmission line electrode voltages based on a floating reference in alow energy voltage sensor network. The system includes a controller, avoltmeter, and an analog to digital converter. The controller includes amemory and an electronic processor. The voltmeter is electricallycoupled to the controller. The voltmeter is also electrically coupled toleads of a high energy transmission line electrode and a floatingreference voltage screen. The floating reference voltage screen ispositioned closer to the high energy transmission line electrode than toa ground plate. The voltmeter and the controller are disconnected fromthe ground plate. The analog to digital converter converts low energyvoltage measurements of a voltage drop between the high energytransmission line electrode and the floating reference voltage screenfor use by the electronic processor. The memory stores capacitance levelparameters for a capacitor formed by the high energy transmission lineelectrode and the floating reference voltage screen and interveningdielectric material. The memory also stores capacitance level parametersfor a capacitor formed by the floating reference voltage screen and theground plate and intervening dielectric material. The memory furtherstores system capacitance and resistance values for components connectedin parallel with the capacitor formed by the high energy analogtransmission line electrode and the floating reference voltage screen.Instructions stored in the memory, when executed by the electronicprocessor, cause the electronic processor to read a voltage level valueoutput from the analog to digital converter of the voltage drop betweenthe high energy analog transmission line electrode and the floatingreference voltage screen. The instructions further cause the electronicprocessor to determine a voltage level for a voltage drop between thehigh energy transmission line electrode and the ground plate based onthe capacitance level parameters for the capacitor formed by the highenergy transmission line electrode and the floating reference voltagescreen stored in the memory, the capacitance level parameters for thecapacitor formed by the floating reference voltage screen and the groundplate stored in the memory, and the system capacitance and resistancevalues for the components connected in parallel with the capacitorformed by the high energy transmission line electrode and the floatingreference voltage screen.

Other aspects and embodiments will become apparent by consideration ofthe detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a circuit diagram of a floating reference low energy analog(LEA) voltage detector system including a voltage divider network,according to some embodiments.

FIG. 2 is a diagram of a recloser switch controller and voltage sensorincluding a floating reference LEA voltage divider network, according tosome embodiments.

FIG. 3 is a block diagram of a recloser controller system thatdetermines voltage levels of a high power transmission line utilizing afloating reference LEA voltage divider network, according to someembodiments.

FIG. 4 is a flow chart of a method for taking LEA voltage measurementswith a floating reference voltage divider network and determiningvoltage of a high power transmission line relative to ground, accordingto some embodiments.

DETAILED DESCRIPTION

Before any embodiments are explained in detail, it is to be understoodthat the embodiments are not limited in their application to the detailsof construction and the arrangement of components set forth in thefollowing description or illustrated in the following drawings. Otherembodiments are possible and embodiments describe are capable of beingpracticed or of being carried out in various ways.

It should also be noted that a plurality of hardware and software baseddevices, as well as a plurality of different structural components, maybe used to implement various embodiments. In addition, it should beunderstood that embodiments may include hardware, software, andelectronic components or modules that, for purposes of discussion, maybe illustrated and described as if the majority of the components wereimplemented solely in hardware. However, one of ordinary skill in theart, and based on a reading of this detailed description, wouldrecognize that, in at least one embodiment, the electronic based aspectsmay be implemented in software (e.g., stored on non-transitorycomputer-readable medium) executable by one or more processors. As such,it should be noted that a plurality of hardware and software baseddevices, as well as a plurality of different structural components maybe utilized to implement various embodiments. Furthermore, and asdescribed in subsequent paragraphs, the specific configurationsillustrated in the drawings are intended to exemplify embodiments andthat other alternative configurations are possible. For example,“controllers” described in the specification can include standardprocessing components, such as one or more processors, one or morecomputer-readable medium modules, one or more input/output interfaces,and various connections (e.g., a system bus) connecting the components.In some instances, the controllers described in the specification may beimplemented in one of or a combination of a general processor, anapplication specific integrated circuit (ASIC), a digital signalprocessor (DSP), a field programmable gate array (FPGA), or the like.

The present disclosure provides, among other things, a system and methodfor determining low energy voltages in a high energy transmission linesystem using a floating reference voltage divider network. This systemmay be used with a measurement device in a transmission line recloservoltage sensor system, as a standalone voltage sensor, or as a voltagesensor for any other device in a power system or in another setting.Some embodiments focus on placement of a voltage screen (voltage sensor)and recloser controller (measurement device) in comparison to a powerline electrode and its voltage and earth ground.

In some embodiments, the voltage sensor is located physically closer tohigh-voltage components than the ground components, resulting in acapacitive voltage sensor that is easily measured by a reclosercontroller device that also has a high-voltage connection and noconnection to earth ground. This improvement in a recloser voltagesensor and recloser controller configuration allows for devices to bemuch more compact and lightweight. These parameters (size and weight)are primarily driven by the required electrical insulation, which isreduced in the present embodiments. The more compact and lightweightdesign options allow for flexibility in placement and configuration ofthe recloser controller device. Moreover, cost savings are achieved whenthe reduction in size and reduced electrical insulation requirements aremet by connecting the recloser controller device at the voltagepotential of the power system.

FIG. 1 is a circuit diagram of a floating reference low energy analog(LEA) voltage detector system including a voltage divider network,according to some embodiments. The circuit diagram in FIG. 1 is a modelof components connected to or a part of a recloser and illustrates avoltage sensor system 100. The voltage sensor system 100 includes aground 110, a high voltage (HV) line electrode 130, a voltage screenelectrode 120, a capacitor 101 (C1), a capacitor 102 (C2), a capacitor103 (C3), and control resistor 104 (R_Control). The capacitor 101 ispositioned in series with the capacitor 102 to divide the voltage dropacross the HV line electrode 130 and the ground 110 at the voltagescreen electrode 120. The capacitor 101 is positioned in parallel withthe capacitor 103 and the control resistor 104.

As noted, the voltage divider network shown in FIG. 1 is a model ofactual components. In one embodiment, the control resistor 104represents the resistance within a voltmeter that is used to measure thevoltage drop across the HV line electrode 130 and the voltage screenelectrode 120. Although the control resistor 104 is shown in the exampleillustrated in 104, in other example, an impedance component orimpedance components other than or in addition to a resistor could beused, for example, a capacitor and/or an inductor. The capacitor 103represents the capacitance of passive components connected in parallelwith the capacitor 101 and the control resistor 104. For example,capacitor 103 represents capacitance in an electrical junction thatconnects the HV line electrode 130 and the voltage screen electrode 120to the voltmeter inputs. The ground 110 may be electrically coupled toearth ground.

The voltage sensor system 100 is a voltage divider network that isdesigned such that a low energy analog (LEA) voltage is measured acrossthe HV line electrode 130 and the voltage screen electrode 120. Thevoltage drop from the HV line electrode 130 to the voltage screenelectrode 120 is much smaller than the voltage drop between the voltagescreen electrode 120 and the ground 110. In this regard, the voltagescreen electrode 120 may be referred to as a floating reference as it isutilized as a reference for a LEA voltmeter measurement relative to theHV line electrode 130, and it is not connected to the ground 110.Furthermore, the voltage sensor system 100 may be referred to as thefloating reference voltage sensor system 100. The voltmeter leads areattached to the HV line electrode 130 and the voltage screen electrode120, and the measured voltage may be orders of magnitude smaller thanthe voltage drop between the HV line electrode 130 and the ground 110.However, embodiments are not limited to a specific relative voltagedifference between the voltmeter measured voltage and the voltage dropbetween the HV line electrode 130 and the ground 110. In someembodiments, the voltage level of the HV line electrode 130 relative tothe ground 110 may be on the order of 10 kV, and the LEA sensed voltageoutput across the HV line electrode 130 and the voltage screen electrode120 may be on the order of 1V. However, the ratio of the voltagemeasured across the HV line electrode 130 and the voltage screenelectrode 120 and the voltage across the HV line electrode 130 and theground 110 is not limited to this example.

In some embodiments, the floating reference voltage sensor system 100 isutilized to determine three phase high voltage line levels in a powerdistribution system. For example, a recloser system may include six suchfloating reference voltage sensor systems 100 including one for each ofthree HV line inputs to the recloser and three HV line outputs exitingfrom the recloser system. However, embodiments of the floating referencevoltage sensor system 100 are not limited to applications in reclosercontroller systems and may be utilized in other HV analog systems.

FIG. 2 is a diagram of a recloser switch controller and voltage sensorincluding a floating reference LEA voltage divider network, according tosome embodiments. Referring to FIG. 2, there is shown a voltage sensorassembly system 200. The example shown includes, among other things, acylindrical ground plate 210, a cylindrical high energy transmissionline electrode 230, a cylindrical voltage screen 220, and a dielectricmaterial 250. The voltage sensor assembly system 200 may be enclosed ina molded insulating housing (not shown). External to the moldedinsulated housing are the components 240 that include a capacitor 203(C3), a control resistor 204, a voltmeter 270, and a recloser controller260.

The components in FIG. 2 correspond with the components represented inthe circuit diagram of FIG. 1. The capacitor 101 represents thecapacitance between the cylindrical high energy transmission lineelectrode 230 and the cylindrical voltage screen 220. The capacitor 102represents the capacitance between the cylindrical voltage screen 220and the cylindrical ground plate 210. The capacitor 103 represents thecapacitor 203, and the control resistor 104 represents the controlresistor 204. The voltage level of the cylindrical ground plate 210 isheld at earth ground.

Although the voltage sensor assembly system 200 is shown as having thecylindrical ground plate 210, the cylindrical high energy transmissionline electrode 230 and the cylindrical voltage screen 220, theseelements are not necessarily cylindrical and may have a differentgeometry suitable to form a capacitive voltage divider network relativeto the high energy transmission line electrode 230. The cylindricalvoltage screen 220 may be referred to as the voltage screen 220 or thefloating reference voltage screen 220, the cylindrical high energytransmission line electrode 230 may be referred to as the transmissionline electrode 230, and the cylindrical ground plate 210 may be referredto as the ground plate 210.

The capacitor 203 is coupled in parallel with the capacitance betweenthe transmission line electrode 230 and the cylindrical voltage screen220. The capacitor 203 represents capacitance of passive components thatare positioned between the voltage sensor assembly system 200 and thevoltmeter 270, and are electrically coupled to the transmission lineelectrode 230 and the cylindrical voltage screen 220. For example, thecapacitor 203 may comprise capacitance of electrical junctions in ajunction box that is disposed between the voltage sensor assembly system200 and both of the voltmeter 270 and recloser controller 260. Thetransmission line electrode 230 may carry a high energy alternatingcurrent.

The voltmeter 270 includes the control resistor 204 electrically coupledto both of the transmission line electrode 230 and the cylindricalvoltage screen 220, in parallel with capacitor 203. The voltmeter 270measures the low energy voltage across the control resistor 204 andconverts the voltage level to a digital value, which may be read by therecloser controller 260. The voltmeter 270 and the recloser controller260 are not connected to the cylindrical ground plate 210 and are notconnected to earth ground (ungrounded). Instead, the voltmeter 270 andthe recloser controller 260 are referenced to floating voltage levels ofthe transmission line electrode 230 and the cylindrical voltage screen220.

In the embodiment shown, the cylindrical voltage screen 220concentrically encircles the transmission line electrode 230. Thecylindrical ground plate 210 concentrically encircles the cylindricalvoltage screen 220, and thus, also concentrically encircles thetransmission line electrode 230. Moreover, the cylindrical voltagescreen 220 is positioned closer to the transmission line electrode 230than to the cylindrical ground plate 210. Leads from the cylindricalvoltage screen 220 and the transmission line electrode 230 areelectrically coupled to inputs of the voltmeter 270. A first capacitanceexists between the transmission line electrode 230 and the cylindricalvoltage screen 220 that corresponds to the capacitor 101 of the voltagedivider network of FIG. 1. A second capacitance exists between thecylindrical voltage screen 220 and the cylindrical ground plate 210 thatcorresponds to the capacitor 102 of the voltage divider network ofFIG. 1. Open internal volumes of the voltage sensor assembly 200 may befilled with the dielectric material 250, for example, a solid dielectricmaterial. The example shown in FIG. 2 forms a voltage divider networkthat is represented by the voltage divider network diagram shown inFIG. 1. The capacitance that is characteristic of the transmission lineelectrode 230 encircled by cylindrical voltage screen 220 withintervening dielectric material 250 is connected in parallel with thecapacitor 203 and the controller resistor 204. All of these componentsare connected in series with the capacitance that is characteristic ofthe cylindrical ground plate 210 encircling the cylindrical ground plate210 with intervening dielectric material 250. A processor in therecloser controller 260 determines a drop in voltage from thetransmission line electrode 230 to the cylindrical ground plate 210 (orearth ground) based on the low energy voltage read from the voltmeter270, and impedance values of the voltage divider network that aredeveloped due to the passive components of the voltage divider networkdescribed with respect to FIGS. 1 and 2.

The cylindrical voltage screen 220 is positioned closer to thetransmission line electrode 230 than to the cylindrical ground plate210. The voltages measured across the control resistor 204 include lowenergy voltages that may be an order of magnitude smaller or multipleorders of magnitude smaller than voltages developed across thecylindrical voltage screen 220 and the cylindrical ground plate 210.FIG. 2 includes an example of linear dimensions for a recloser voltagesensor assembly 200. However, these specific linear dimensions areincluded to provide an example. In other embodiments, the dimensions maybe different. In addition, although the voltage sensor assembly system200 shown in FIG. 2 comprises a voltage screen and a ground plateforming concentric cylinders about the transmission line electrode 230,other configurations may be used. The capacitances that correspond tocapacitor 101 and capacitor 102 of the voltage divider network of FIG. 1could also be created by plates, rods, spheres, or other shapes, placednear each other with the dielectric material 250 between them. Thedimensions and placement of the shapes inside the dielectric materialalso has almost limitless configurations, depending on the intendedpower system voltage, dielectric material used, and capabilities of thevoltmeter 270.

FIG. 3 is a block diagram of a recloser controller system thatdetermines voltage levels of a high power transmission line utilizing afloating reference LEA voltage divider network, according to someembodiments. A recloser controller and voltage measurement system 300includes the recloser controller 260 and the voltmeter 270. Thevoltmeter 270 includes, among other things, the control resistor 204, ananalog to digital (A/D) converter 332, and voltmeter inputs 320 and 330that are electrically coupled to leads of the voltage screen 220 and thetransmission line electrode 230. However, although the control resistor104 is shown and referred to as a resistor, the control resistor 104 maycomprise or represent an impedance component, for example, a capacitorand/or an inductor. The recloser controller 260 includes, among otherthings, a processor 338, a memory 340, a graphical user interface 334,an interface 370, a wireless interface 350, a global positioningsatellite (GPS) receiver 352, a display 354, a speaker 356, networkinterfaces 364, and a user interfaces 366. The voltmeter 270 and therecloser controller 260 are not connected to ground.

The memory 340 may store program instructions 342 for estimatingalternating current (AC) voltage across the transmission line electrode230 to the ground plate 210 based on measurements from the floatingreference voltage divider circuit taken from the transmission lineelectrode 230 to the voltage screen 220, described with respect to FIGS.1 and 2. The memory 340 may store low voltage voltmeter readings fromthe A/D converter 332 and/or high voltage estimations 344.

Memory 346 may store configuration parameters for passive components ofthe voltage sensor assembly system 200 floating reference voltagedivider network and passive components of the external components 240,including parameters for the capacitance between the transmission lineelectrode 230 and the voltage screen 220, the capacitance between thevoltage screen 220 and the ground plate 210, the capacitor 203 and thecontrol resistor 204. Program instructions 348 for recloser switch andrecloser controller systems operations may be stored in the memory 340.The configuration parameters and program instructions may be utilized tocompensate or calibrate for any inaccuracies of the magnitude or phaseof a voltage reading.

Various configurations of the elements of the recloser controller andvoltage measurement system 300 may be implemented. For example, thevoltmeter 270 may be located outside of the recloser and electricallycoupled to the recloser controller 260, or it may be integrated with therecloser controller 260 in a single housing. In some embodiments, thevoltmeter 270 and recloser controller 260 may be positioned near to arecloser switch in a junction box or some location that is moreaccessible by a user. The distance between the recloser switch and thevoltmeter 270 and recloser controller 260 is not critical for theperformance of the sensor, and it is typically limited by othercomponents for the recloser's operation

Embodiments of the disclosure as described herein, for example,embodiments directed to a low energy analog voltage sensor comprising afloating reference voltage divider network and determining high energyanalog transmission line electrode voltages relative to ground may beexecuted on one or more ungrounded computer systems, ungroundedelectronic processors, or ungrounded controllers that may interact withvarious other devices. One such recloser computer system is illustratedby FIG. 3 as the recloser controller and voltage measurement system 300,which may be referred to as the computer system 300. The computer system300 may include any of various types of devices, including, but notlimited to, a programmable electronic processor, for example, amicroprocessor, an ASIC, a mobile computing device, a personal computersystem, desktop computer, laptop, notebook, or netbook computer,mainframe computer system, mobile telephone, workstation, networkcomputer, various peripheral devices, or another type of computing orelectronic device.

In the illustrated embodiment, computer system 300 includes one or moreprocessors 338 coupled to the memory 340. Computer system 300 furtherincludes a network interface 364 coupled to interface 370, and one ormore user input/output devices 366, such as cursor control device,keyboard, and a display(s). In some embodiments, it is contemplated thatembodiments may be implemented using a single instance of computersystem 300, while in other embodiments multiple such systems, ormultiple nodes making up computer system 300, may be configured to hostdifferent portions or instances of embodiments. For example, in oneembodiment some elements may be implemented via one or more nodes ofcomputer system 300 that are distinct from those nodes implementingother elements.

The memory 340 may be configured to store program instructions and/ordata accessible by processor 338. In various embodiments, the memory 340may be implemented using suitable memory technology, such as staticrandom access memory (SRAM), synchronous dynamic RAM (SDRAM),nonvolatile/Flash-type memory, or another type of memory. In theillustrated embodiment, program instructions and data implementingdesired functions, such as those described above for variousembodiments, are stored within the memory 340 as recloser switchcontroller program instructions 348, high voltage estimationinstructions 342, and data storage 344 and 346. In other embodiments,program instructions and/or data may be received, sent or stored upondifferent types of computer-accessible media or on similar mediaseparate from the memory 340 or computer system 300. Moreover, in someembodiments, a database (not shown) accessible via the network interface364 may store, among other things, floating reference voltage dividerparameters, LEA measurement values, determined high energy linevoltages, voltage estimation instructions, and voltmeter parameters.Generally speaking, a computer-accessible medium may include storagemedia or memory media such as magnetic or optical media, e.g., a flashmemory card, a disk, or CD/DVD-ROM coupled to computer system 300 viainterface 370.

In one embodiment, interface 370 may be configured to coordinate I/Otraffic between processor 338, the memory 340, and any peripheraldevices, including via the network interfaces 364 or other peripheralinterfaces, such as input/output devices 366 or display 354. In someembodiments, interface 370 may perform any necessary protocol, timing orother data transformations to convert data signals from one component(e.g., the memory 340) into a format suitable for use by anothercomponent (e.g., processor 338). In some embodiments, interface 370 mayinclude support for devices attached through various types of peripheralbuses, such as a variant of the Peripheral Component Interconnect (PCI)bus standard or the Universal Serial Bus (USB) standard, for example. Insome embodiments, the function of interface 370 may be split into two ormore separate components, such as a north bridge and a south bridge, forexample. In addition, in some embodiments some or all of thefunctionality of interface 370, such as an interface to the memory 340,may be incorporated directly into processor 338.

Network interfaces 364 may be configured to allow data to be exchangedbetween computer system 300 and other devices attached to a network,such as other computer systems, a database, or between nodes of computersystem 300. In various embodiments, network interface 364 may supportcommunication via wired or wireless general data networks, such as anysuitable type of Ethernet network, for example; viatelecommunications/telephony networks such as analog voice networks ordigital fiber communications networks; via storage area networks such asFiber Channel SANs, or via any other suitable type of network and/orprotocol. In some embodiments, the processor 338 may communicate voltagelevels determined by the voltmeter 270 or the high-voltage estimationmodule program instructions 342 to remote computer systems via thenetwork interfaces 364 or the wireless interface 350, for example, via acellular network. The communications may include location informationfor the recloser controller 260 or the coupled recloser switch based onlocation information determined by the GPS receiver 352. Furthermore,the low energy or high energy voltage levels, the location information,and/or various information about an attached recloser system may bedisplayed via the graphical user interface 334 and/or the display 354.The user interfaces 366 may receive user commands or configurationinformation for the recloser controller 260 and/or the voltmeter 270.

Input/output devices connected via the user interfaces 366 may, in someembodiments, include one or more display terminals, keyboards, keypads,touchpads, scanning devices, voice or optical recognition devices, orany other devices suitable for entering or retrieving data by one ormore computer system 300. Multiple input/output devices may be presentin computer system 300 or may be distributed on various nodes ofcomputer system 300. In some embodiments, similar input/output devicesmay be separate from computer system 300 and may interact with one ormore nodes of computer system 300 through a wired or wirelessconnection, such as over network interface 364.

Those skilled in the art will also appreciate that, while various itemsare illustrated as being stored in memory or on storage while beingused, these items or portions of them may be transferred between memoryand other storage devices for purposes of memory management and dataintegrity. Alternatively, in other embodiments some or all of thesoftware components may execute in memory on another device andcommunicate with the illustrated computer system 300 via inter-computercommunication. Some or all of the system components or data structuresmay also be stored (e.g., as instructions or structured data) on acomputer-accessible medium or a portable article to be read by anappropriate drive, various examples of which are described above. Insome embodiments, instructions stored on a computer-accessible mediumseparate from computer system 300 may be transmitted to computer system300 via transmission media or signals such as electrical,electromagnetic, or digital signals, conveyed via a communication mediumsuch as a network and/or a wireless link. Various embodiments mayfurther include receiving, sending or storing instructions and/or dataimplemented in accordance with the foregoing description upon acomputer-accessible medium. Accordingly, the present embodiments may bepracticed with other computer system configurations.

FIG. 4 is a flow chart of a method for taking LEA voltage measurementswith a floating reference voltage divider network and determiningvoltage of a high power transmission line relative to ground, accordingto some embodiments.

In step 410, floating reference LEA voltage sensor and measurementparameters may be stored in the memory 346. For example, the capacitancebetween the transmission line electrode 230 and the voltage screen 220,the capacitance between the voltage screen 220 and the ground plate 210,the capacitor 203 and the control resistor 204 may be stored in thememory 346. In other embodiments, the values for the capacitor 101, thecapacitor 102, the capacitor 103, and the control resistor 104 may bestored in the memory 346.

In step 420, leads from the transmission line electrode 230 and thevoltage screen 220 are electrically coupled to the voltmeter inputs 320and 330, without connecting the voltmeter 270 or the recloser controller260 to the ground plate 210 or earth ground. The capacitance between thetransmission line electrode 230 and the voltage screen 220 is connectedin parallel with the capacitor 203 and the control resistor 204.

In step 430, the voltage is measured across the electrode 230 andvoltage screen 220 and is converted to digital values by the A/Dconverter 332.

In step 440, voltage levels are estimated for the voltage drop from thetransmission line electrode 230 to the ground plate 210 that is held atearth ground. The recloser controller 260 reads the A/D convertedvoltmeter 270 output. The voltage levels from ground plate 210 to thetransmission line electrode 230 are determined based on the low energymeasurements and the parameters stored in memory 346 including thecapacitance between the transmission line electrode 230 and the voltagescreen 220, the capacitance between the voltage screen 220 and theground plate 210, the capacitor 203, and the control resistor 204. Inother embodiments, the values for the capacitor 101, the capacitor 102,the capacitor 103, and the control resistor 104 are used in the earthground to high AC voltage estimation.

The various methods as illustrated in the Figures and described hereinrepresent example embodiments of methods. The methods may be implementedin software, hardware, or a combination thereof. The order of method maybe changed, and various elements may be added, reordered, combined,omitted, modified, etc.

Various modifications and changes may be made as would be obvious to aperson skilled in the art having the benefit of this disclosure. It isintended that the present embodiments embrace all such modifications andchanges and, accordingly, the above description to be regarded in anillustrative rather than a restrictive sense.

Thus, the embodiments provide, among other things, systems and methodsfor dynamically configuring display of a plurality of documents based ona document review task associated with the plurality of documents.Various features and advantages are set forth in the following claims.

We claim:
 1. A voltage sensor system for measuring low energy voltage ina high energy transmission line electrode divider network, the systemcomprising: a high energy transmission line electrode; a floatingreference voltage screen; a ground plate; wherein the floating referencevoltage screen is positioned between the high energy transmission lineelectrode and the ground plate at a distance from the high energytransmission line electrode that is shorter than a distance between theground plate and the floating reference voltage screen; and a firstconductive lead electrically coupling the high energy transmission lineelectrode to a first input of a voltmeter connected to a controller anda second conductive lead electrically coupling the floating referencevoltage screen to a second input of the voltmeter connected to thecontroller for measuring an alternating voltage drop across the highenergy transmission line electrode and the floating reference voltagescreen by electronics of the voltmeter connected to the controller;wherein the controller and the voltmeter are both disconnected from theground plate.
 2. The system of claim 1, wherein the floating referencevoltage screen and the ground plate form a voltage divider network forthe measuring of the alternating voltage drop when the first conductivelead is connected with the first input of the voltmeter and the secondconductive lead is connected with the second input of the voltmeter anda capacitor is connected in parallel with the first conductive lead andthe second conductive lead.
 3. The system of claim 1, wherein the highenergy transmission line electrode, the floating reference voltagescreen and the ground plate are enclosed in a housing, and the openinternal volumes within the housing are filled with a dielectricmaterial.
 4. The system of claim 1, wherein the alternating voltage dropacross the high energy transmission line electrode and the floatingreference voltage screen is smaller than a voltage drop between thefloating reference voltage screen and the ground plate.
 5. The system ofclaim 1, wherein the voltmeter comprises an analog to digital converter.6. The system of claim 5, wherein the controller reads a voltage dropvalue output from the analog to digital converter that represents thevoltage drop across the high energy transmission line electrode and thefloating reference voltage screen.
 7. The system of claim 6, wherein thecontroller determines a voltage drop across the high energy transmissionline electrode and the ground plate based on the voltage drop valueoutput from the analog to digital converter and a capacitanceelectrically coupled between the high energy transmission line electrodeand the floating reference voltage screen, and a capacitanceelectrically coupled between the floating reference voltage screen andthe ground plate.
 8. A method for measuring low energy voltage in a highenergy transmission line electrode sensor network, the methodcomprising: positioning a floating reference voltage screen between ahigh energy transmission line electrode and a ground plate at a distancefrom the high energy transmission line electrode that is shorter than adistance between the ground plate and the floating reference voltagescreen; electrically coupling a first conductive lead to the high energytransmission line electrode and to a first input of a voltmeterconnected to a controller; electrically coupling a second conductivelead to the floating reference voltage screen and to a second input ofthe voltmeter connected to the controller; and measuring a voltage dropacross the high energy transmission line electrode and the floatingreference voltage screen by electronics of the voltmeter connected tothe controller; wherein the controller and the voltmeter are bothdisconnected from the ground plate.
 9. The method of claim 8, whereinthe floating reference voltage screen and the ground plate form avoltage divider network for the measuring of the voltage drop when thefirst conductive lead is connected with the first input of the voltmeterand the second conductive lead is connected with the second input of thevoltmeter and a capacitor is connected in parallel with the firstconductive lead and the second conductive lead.
 10. The method of claim8, wherein the high energy transmission line electrode, the floatingreference voltage screen and the ground plate are enclosed in a housing,and the open internal volumes within the housing are filled with a soliddielectric material.
 11. The method of claim 8, wherein the voltage dropacross the high energy transmission line electrode and the floatingreference voltage screen is smaller than a voltage drop between thefloating reference voltage screen and the ground plate.
 12. The methodof claim 8, wherein the voltmeter comprises an analog to digitalconverter.
 13. The method of claim 12, wherein the controller reads avoltage drop value output from the analog to digital converter thatrepresents the voltage drop across the high energy transmission lineelectrode and the floating reference voltage screen.
 14. The method ofclaim 13, wherein the controller determines a voltage drop across thehigh energy transmission line electrode and the ground plate based onthe voltage drop value output from the analog to digital converter and acapacitance electrically coupled between the high energy transmissionline electrode and the floating reference voltage screen, and acapacitance electrically coupled between the floating reference voltagescreen and the ground plate.
 15. A system for determining high energytransmission line electrode voltages based on a floating reference in alow energy voltage sensor network, the system comprising: a controllercomprising a memory and an electronic processor; a voltmeterelectrically coupled to the controller and electrically coupled to leadsof a high energy transmission line electrode and a floating referencevoltage screen, wherein the floating reference voltage screen ispositioned closer to the high energy transmission line electrode than toa ground plate, wherein the voltmeter and the controller aredisconnected from the ground plate; and an analog to digital converterfor converting low energy voltage measurements of a voltage drop betweenthe high energy transmission line electrode and the floating referencevoltage screen for use by the electronic processor; the memory storing:capacitance level parameters for a capacitor formed by the high energytransmission line electrode and the floating reference voltage screenand intervening dielectric material, capacitance level parameters for acapacitor formed by the floating reference voltage screen and the groundplate and intervening dielectric material, system capacitance andresistance values for components connected in parallel with thecapacitor formed by the high energy transmission line electrode and thefloating reference voltage screen, and instructions stored in the memorythat when executed by the electronic processor cause the electronicprocessor to: read a voltage level output from the analog to digitalconverter of the voltage drop between the high energy transmission lineelectrode and the floating reference voltage screen, and determine avoltage level for a voltage drop between the high energy transmissionline electrode and the ground plate based on: the capacitance levelparameters for the capacitor formed by the high energy transmission lineelectrode and the floating reference voltage screen stored in thememory, the capacitance level parameters for the capacitor formed by thefloating reference voltage screen and the ground plate stored in thememory, and the system capacitance and resistance values for thecomponents connected in parallel with the capacitor formed by the highenergy transmission line electrode and the floating reference voltagescreen.
 16. The system of claim 15, further comprising a wirelessinterface, wherein the voltage level for the voltage drop between thehigh energy transmission line electrode and the ground plate istransmitted to a remote computer system via a cellular network.
 17. Thesystem of claim 15, wherein the floating reference voltage screen andthe ground plate form a voltage divider network for measuring the lowenergy voltage measurements when the floating reference voltage screenand the high energy transmission line electrode are connected inparallel with the voltmeter and a system capacitance.
 18. The system ofclaim 15, wherein the high energy transmission line electrode, thefloating reference voltage screen, and the ground plate are enclosed ina housing, and the open internal volumes within the housing are filledwith a solid dielectric material.
 19. The system of claim 15, wherein avoltage drop across the high energy transmission line electrode and thefloating reference voltage screen is smaller than a voltage drop betweenthe floating reference voltage screen and the ground plate.
 20. Thesystem of claim 15, wherein the floating reference voltage screen is acylindrical voltage screen, the ground plate is a cylindrical groundplate, and the ground plate is electrically coupled to earth ground.